English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The axion is much lighter than all other degrees of freedom introduced by thePeccei-Quinn mechanism to solve the strong CP problem. It is therefore naturalto use an effective field theory (EFT) to describe its interactions. Loopprocesses calculated in the EFT may, however, explicitly depend on theultraviolet cutoff. In general the UV cutoff is not uniquely defined, but thedimensionful couplings suggest to identify it with the Peccei-Quinnsymmetry-breaking scale. An example are $K \rightarrow \pi + a$ decays thatwill soon be tested to improved precision in NA62 and KOTO and whose amplitudeis dominated by the term logarithmically dependent on the cutoff. In thispaper, we critically examine the adequacy of using such a naive EFT approach tostudy loop processes by comparing EFT calculations with ones performed incomplete QCD axion models. In DFSZ models, for example, the cutoff is found tobe set by additional Higgs degrees of freedom and to therefore be much closerto the electroweak scale than to the Peccei-Quinn scale. In fact, there arenon-trivial requirements on axion models where the cutoff scale of loopprocesses is close to the Peccei-Quinn scale, such that the naive EFT result isreproduced. This suggests that the existence of a suitable UV embedding mayimpose restrictions on axion EFTs. We provide an explicit construction of amodel with suitable fermion couplings and find promising prospects for NA62 andIAXO.

Leading Logs in QCD Axion Effective Field Theory